1. Field of the Invention
The present invention relates to a method and apparatus for picking and placing tires onto stacks as well as picking and placing stacks of tires onto pallets or conveyors.
2. Description of the Related Art
Tires for automobiles and other vehicles come in all different sizes and types. Tires are made to fit various wheel or rim diameters. The term "bead" is used to refer to the inner diameter of the tire. For example, a 14-inch bead tire is for a 14-inch diameter wheel or rim. In addition to the bead, tires are also sized by their width and outside diameter (O.D.) Various width tires are made in each of the bead sizes. Similarly, various outside diameter (O.D.) tires are made for each of the bead and width sizes. Thus, a 14-inch bead tire may have any of a variety of widths and/or heights associated with it. Vehicle tires have a bead typically in the range of 13 inches to 20 inches.
In addition to the above dimensional properties of tires, tire manufacturers make a variety of tread types and side wall types for particular sizes of tires. Thus, it is easy to understand that a tire manufacturer makes a large number of types of individual tires. During the manufacture of the tires, the finished tires are typically transported by conveyor to the end of the manufacturing line. Upon reaching the end of the manufacturing line. the tires are palletized in preparation for shipping or transportation. Typically, the tires coming off the manufacturing line include a variety of different types of tires. Oftentimes, it is desirable that the tires be placed onto stacks according to the type of tire.
Previously, a robotic tire end effector assembly, designed by C&D Robotics of Beaumont, Tex., has been used to pick a single tire from the end of the conveyor line and place the tire onto a pallet. This process of picking and placing a single tire was repeated over and over and over again. Typically, a separate pallet was required for each of the tire types. Typically, four stacks of tires can be placed onto a pallet. This prior art robotic device picked up the tire by positioning a robotic tire end effector assembly within the bead of the tire. Three equidistantly spaced radial wings were then outwardly extended to bear against the lower bead of the tire.
It is desirable to have a robotic tire end effector assembly that is capable of picking up a stack of tires. It is also desirable to have a robotic tire end effector assembly that can pick up and transport a stack of tires without damaging the tires. It is also desirable that the robotic tire end effector assembly be capable of handling a variety of sizes and types of tires. It is also desirable to have a tire handling system that is quick, efficient, and reliable at picking up and palletizing tires of various types and sizes.